I went through the entire convo to see what happened, it was pretty much mostly all jokes not meant to be mean in any way shape or form, Flatflyer just sort of left a couple hours later.
i think the problem that flat has, and i can't speak for him so this is just my guess, is that people are/were making a joke of his art. and i can understand why that would be upsetting. as an artist of any description, regardless of skill, you probably want your work to be taken seriously for what it is, and it's frustrating when people don't. i don't think flat is getting upset over nothing, he's getting upset over not being happy with his work, and having those feelings confirmed by other people not taking his work seriously.
that's my armchair psychology